Emil Rosqvist

The nature of terminal functional groups in passivating agents influences the optoelectronic properties and photovoltaic performance of perovskite solar cells.

The proliferation of human cervical cancer (Hela) cells was investigated on a series of nanostructured polymer latex surfaces. The physico-chemical properties of the surfaces, composed of mixtures of polystyrene and acrylonitrile butadiene styrene dispersions, were precisely controlled in the nanoscale range by adjusting the mixing ratio of the components and thermal treatment. In addition, the proliferation response of HeLa cells was compared to that of human dermal fibroblast (HDF) cells. A low dispersive surface energy and peak or valley dominance (S_pk/S_vk) were observed to increase the proliferation yield of the Hela cells. The HDF cells were less influenced by the surface chemistry and showed improved proliferation on surfaces without dominant peak or valley features (S_pk and S_vk). The observed changes in Hela cell behaviour underscored the critical role of material surface properties in influencing cellular responses, with more significant accumulation of nuclear patterning of filamentous actin (F-actin) on stiffer and smoother surfaces (e.g., borosilicate glass) due to higher mechanical stress. A more dynamic reorganisation of the cytoskeleton was observed for cells grown on polymer surfaces with moderate roughness and surface energy. These results emphasise the importance of characterising and tuning surface properties to accommodate the specific behaviours of different cell types.

Global antimicrobial resistance poses a major threat to human health and is largely driven by bacterial biofilms, which demonstrate significantly greater antibiotic resistance than planktonic bacteria. While most biofilm research targets the development of antibiofilm surfaces, materials that intentionally promote biofilm formation are crucial for creating screening tools to discover new antibiofilm agents. The transition from static to flow‐through assay systems is also necessary to increase the methodological readiness of antibiofilm research. This study evaluates the feasibility of an emerging polymer platform, off‐stoichiometry thiol‐ene (OSTE), in supporting Staphylococcus aureus biofilms. OSTE polymers provide versatile options for rapid prototyping of microfluidic devices, with unique opportunities for on‐chip oxygen management. Here, the impacts of OSTE's key materials properties on S. aureus adhesion, biofilm viability, biomass, and metabolic activity are systematically examined in comparison to polystyrene, the current standard in microwell plate‐based biofilm assays. Additionally, the composition of the extracellular polymer substances matrix and antimicrobial susceptibility are investigated to determine the most suitable OSTE composition for microfluidic S. aureus biofilm cultures. The results confirm compatibility with S. aureus biofilms, supported by atomic force microscopy analysis of biofilm morphologies under static and microfluidic conditions.

Organic electrochemical transistors (OECTs) have been proven beneficial for bioelectronic applications. However, the demand for reliable and fast fabrication methods has not yet been fully met. In this work, OECTs are fabricated using direct ink writing (DIW). This method is cleanroom‐free and can be done without using lithography techniques. These devices are characterized and benchmarked against devices fabricated using spin‐coating and drop‐casting deposition approaches. Response time as well as the product of carrier charge mobility and volumetric capacitance are found to be higher using the DIW fabrication approach compared to standard deposition techniques. In addition, a testing process is designed to systematically evaluate the operational degradation of the semiconductor channel. This test enables identical conditions for all tested devices while providing comparable output. Thicker channels show better stability, while thinner channels are proved to be better transistors. Finally, the degradation issues and instability of these devices are discussed.

Organic electrochemical transistors (OECTs) are widely employed in several bioelectronic applications such as biosensors, logic circuits, and neuromorphic engineering, providing a seamless link between the realm of biology and electronics. More specifically, OECTs are endowed with remarkable signal amplification, the ability to operate in an aqueous environment, and the effective transduction of ionic to electrical signals. One main limiting factor preventing OECTs’ wide use is the need for microfabrication processes, typically requiring specialized equipment. From this perspective, a robust and cost-effective production protocol to achieve high-performing OECT would be desirable. Herein, a straightforward stencil-printed OECT fabrication procedure is proposed, where the electrical performance can be controlled by adjusting the electronic channel fabrication conditions. An experimental design approach is undertaken to optimize OECT figures of merit by varying key parameters such as the annealing temperature and time, as well as the transistor active channel length. The resulting OECT devices, fabricated through a high-yield, cost-effective, and fast stencil printing technique, feature large transconductance values at low operating voltages. The experimental design allowed for minimizing the threshold voltage (V_T = 260 mV) while keeping a high on/off ratio (7 × 10³). A signal-to-noise ratio as high as 40 dB was obtained, which is among the highest for OECTs, operating in an aqueous electrolyte operated in a DC mode. An atomic force microscopy (AFM) characterization has been undertaken to analyze the channel morphology in the OECTs, correlating the annealing conditions with the charge transport properties.

Efficient antimicrobial hydrogels are fabricated by digital light processing (DLP) printing out of a sustainable resin, which is formulated with methacrylated O -acetyl-galactoglucomannan and lignin nanospheres decorated with silver nanoparticles.

Illustrating the versatility, processability and reliability of a paper-based screening platform for biological studies with cell-material interaction studies and drug testing.